Remove INET_ADDRSTRLEN limit for symbolic hostnames and optimize socket connections.

core/federated/RTI/rti_remote.c

@@ -636,23 +636,20 @@ void handle_address_query(uint16_t fed_id) {
 
   int32_t server_port;
   uint32_t* ip_address;
-  char* server_host_name;
+  uint32_t temp = 0;
 
   LF_MUTEX_LOCK(&rti_mutex);
   // Check if the RTI has initialized the remote federate's network abstraction.
   if (remote_fed->net == NULL) {
     // RTI has not set up the remote federate. Respond with -1 to indicate an unknown port number.
     server_port = -1;
-    uint32_t temp = 0;
     ip_address = &temp;
-    server_host_name = "localhost";
   } else {
     // The network abstraction is initialized, but the RTI might still not know the port number. This can happen if the
     // RTI has not yet received a MSG_TYPE_ADDRESS_ADVERTISEMENT message from the remote federate. In such cases, the
     // returned port number might still be -1.
     server_port = ((socket_priv_t*)remote_fed->net)->server_port;
     ip_address = (uint32_t*)&((socket_priv_t*)remote_fed->net)->server_ip_addr;
-    server_host_name = ((socket_priv_t*)remote_fed->net)->server_hostname;
   }
 
   encode_int32(server_port, (unsigned char*)&buffer[1]);
@@ -669,8 +666,7 @@ void handle_address_query(uint16_t fed_id) {
     tracepoint_rti_to_federate(send_ADR_QR_REP, fed_id, NULL);
   }
 
-  LF_PRINT_DEBUG("Replied to address query from federate %d with address %s:%d.", fed_id, server_host_name,
-                 server_port);
+  LF_PRINT_DEBUG("Replied to address query from federate %d", fed_id);
 }
 
 void handle_address_ad(uint16_t federate_id) {
@@ -1057,7 +1053,6 @@ void send_reject(net_abstraction_t net_abs, unsigned char error_code) {
   }
   // Close the network abstraction without reading until EOF.
   shutdown_net(net_abs, false);
-  net_abs = NULL;
   LF_MUTEX_UNLOCK(&rti_mutex);
 }
 
@@ -1427,7 +1422,6 @@ void lf_connect_to_federates(net_abstraction_t rti_net) {
         lf_print_warning("RTI failed to authenticate the incoming federate.");
         // Close the network abstraction without reading until EOF.
         shutdown_net(fed_net, false);
-        fed_net = NULL;
         // Ignore the federate that failed authentication.
         i--;
         continue;
@@ -1496,7 +1490,6 @@ void* respond_to_erroneous_connections(void* nothing) {
     }
     // Close the network abstraction without reading until EOF.
     shutdown_net(fed_net, false);
-    fed_net = NULL;
   }
   return NULL;
 }

core/federated/RTI/rti_remote.h

@@ -271,7 +271,7 @@ void handle_address_query(uint16_t fed_id);
  * byte. The RTI will keep a record of this number in the .server_port
  * field of the _RTI.federates[federate_id] array of structs.
  *
- * The server_hostname and server_ip_addr fields are assigned
+ * The server_ip_addr field is assigned
  * in lf_connect_to_federates() upon accepting the socket
  * from the remote federate.
  *

core/federated/federate.c

@@ -1753,13 +1753,10 @@ void lf_connect_to_federate(uint16_t remote_federate_id) {
   assert(port > 0);
   uint16_t uport = (uint16_t)port;
 
-  char hostname[INET_ADDRSTRLEN];
-  inet_ntop(AF_INET, &host_ip_addr, hostname, INET_ADDRSTRLEN);
-
-  socket_connection_params_t params;
+  socket_connection_params_t params = {0};
   params.type = TCP;
   params.port = uport;
-  params.server_hostname = hostname;
+  params.server_ip_addr = &host_ip_addr;
   net_abstraction_t net = connect_to_net((net_params_t)&params);
   if (net == NULL) {
     lf_print_error_and_exit("Failed to connect to federate.");
@@ -1837,7 +1834,7 @@ void lf_connect_to_rti(const char* hostname, int port) {
   hostname = federation_metadata.rti_host ? federation_metadata.rti_host : hostname;
   port = federation_metadata.rti_port >= 0 ? federation_metadata.rti_port : port;
 
-  socket_connection_params_t params;
+  socket_connection_params_t params = {0};
   params.type = TCP;
   params.port = port;
   params.server_hostname = hostname;
@@ -2013,7 +2010,7 @@ void* lf_handle_p2p_connections_from_federates(void* env_arg) {
     net_abstraction_t net = accept_net(_fed.server_net);
     if (net == NULL) {
       lf_print_warning("Federate failed to accept the network abstraction.");
-      return NULL;
+      continue;
     }
     LF_PRINT_LOG("Accepted new connection from remote federate.");
 
@@ -2034,7 +2031,6 @@ void* lf_handle_p2p_connections_from_federates(void* env_arg) {
         write_to_net(net, 2, response);
       }
       shutdown_net(net, false);
-      net = NULL;
       continue;
     }
 
@@ -2055,7 +2051,6 @@ void* lf_handle_p2p_connections_from_federates(void* env_arg) {
         write_to_net(net, 2, response);
       }
       shutdown_net(net, false);
-      net = NULL;
       continue;
     }
 

network/api/socket_common.h

@@ -133,6 +133,9 @@ typedef struct socket_connection_params_t {
 
   /** @brief Hostname of the remote server. */
   const char* server_hostname;
+
+  /** @brief IP address of the remote server. If provided, bypasses DNS resolution. */
+  struct in_addr* server_ip_addr;
 } socket_connection_params_t;
 
 /**
@@ -149,8 +152,6 @@ typedef struct socket_priv_t {
   uint16_t port;
   /** @brief The desired port specified by the user on the command line. */
   uint16_t user_specified_port;
-  /** @brief Human-readable IP address of the federate's socket server. */
-  char server_hostname[INET_ADDRSTRLEN];
   /** @brief Port number of the socket server of the federate. The port number will be -1 if there is no server or if
    * the RTI has not been informed of the port number. */
   int32_t server_port;
@@ -215,10 +216,11 @@ int accept_socket(int socket);
  *
  * @param sock The socket file descriptor that has already been created (using `socket()`).
  * @param hostname The hostname or IP address of the server to connect to.
+ * @param ip_addr The IPv4 address to connect to. If non-NULL, bypasses DNS lookup of hostname.
  * @param port The port number to connect to. If 0 is specified, a default port range will be used.
  * @return 0 on success, -1 on failure, and `errno` is set to indicate the specific error.
  */
-int connect_to_socket(int sock, const char* hostname, int port);
+int connect_to_socket(int sock, const char* hostname, struct in_addr* ip_addr, int port);
 
 /**
  * @brief Read the specified number of bytes from the specified socket into the specified buffer.
@@ -296,7 +298,7 @@ bool is_socket_open(int socket);
  * @ingroup Network
  *
  * Get the connected peer name from the connected socket.
- * Set it to the server_ip_addr. Also, set server_hostname if LOG_LEVEL is higher than LOG_LEVEL_DEBUG.
+ * Set it to the server_ip_addr. Also, print server's hostname if LOG_LEVEL is higher than LOG_LEVEL_DEBUG.
  *
  * @param priv The socket_priv struct.
  * @return 0 for success, -1 for failure.

network/impl/src/lf_socket_support.c

@@ -30,7 +30,6 @@ net_abstraction_t initialize_net() {
   priv->socket_descriptor = -1;
 
   // Federate initialization
-  strncpy(priv->server_hostname, "localhost", INET_ADDRSTRLEN);
   priv->server_ip_addr.s_addr = 0;
   priv->server_port = -1;
 
@@ -83,11 +82,11 @@ net_abstraction_t connect_to_net(net_params_t params) {
   socket_priv_t* priv = (socket_priv_t*)net;
   socket_connection_params_t* sock_params = (socket_connection_params_t*)params;
   priv->server_port = sock_params->port;
-  memcpy(priv->server_hostname, sock_params->server_hostname, INET_ADDRSTRLEN);
   // Create the client network abstraction.
   create_client(net);
   // Connect to the target server.
-  if (connect_to_socket(priv->socket_descriptor, priv->server_hostname, priv->server_port) != 0) {
+  if (connect_to_socket(priv->socket_descriptor, sock_params->server_hostname, sock_params->server_ip_addr,
+                        priv->server_port) != 0) {
     lf_print_error("Failed to connect to socket.");
     return NULL;
   }

network/impl/src/socket_common.c

@@ -177,14 +177,10 @@ int get_peer_address(socket_priv_t* priv) {
   priv->server_ip_addr = peer_addr.sin_addr;
 
 #if LOG_LEVEL >= LOG_LEVEL_DEBUG
-  // Create the human readable format and copy that into
-  // the .server_hostname field of the federate.
+  // Create the human readable format for logging purposes
   char str[INET_ADDRSTRLEN + 1];
   inet_ntop(AF_INET, &priv->server_ip_addr, str, INET_ADDRSTRLEN);
-  strncpy(priv->server_hostname, str, INET_ADDRSTRLEN - 1); // Copy up to INET_ADDRSTRLEN - 1 characters
-  priv->server_hostname[INET_ADDRSTRLEN - 1] = '\0';        // Null-terminate explicitly
-
-  LF_PRINT_DEBUG("Got address %s", priv->server_hostname);
+  LF_PRINT_DEBUG("Got address %s", str);
 #endif
   return 0;
 }
@@ -218,20 +214,28 @@ int accept_socket(int socket) {
   return socket_id;
 }
 
-int connect_to_socket(int sock, const char* hostname, int port) {
+int connect_to_socket(int sock, const char* hostname, struct in_addr* ip_addr, int port) {
   struct addrinfo hints;
-  struct addrinfo* result;
+  struct addrinfo* result = NULL;
   int ret = -1;
 
-  memset(&hints, 0, sizeof(hints));
-  hints.ai_family = AF_INET;       /* Allow IPv4 */
-  hints.ai_socktype = SOCK_STREAM; /* Stream socket */
-  hints.ai_protocol = IPPROTO_TCP; /* TCP protocol */
-  hints.ai_addr = NULL;
-  hints.ai_next = NULL;
-  hints.ai_flags = AI_NUMERICSERV; /* Allow only numeric port numbers */
-
   uint16_t used_port = (port == 0) ? DEFAULT_PORT : (uint16_t)port;
+  struct sockaddr_in direct_addr;
+
+  if (ip_addr == NULL) {
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = AF_INET;       /* Allow IPv4 */
+    hints.ai_socktype = SOCK_STREAM; /* Stream socket */
+    hints.ai_protocol = IPPROTO_TCP; /* TCP protocol */
+    hints.ai_addr = NULL;
+    hints.ai_next = NULL;
+    hints.ai_flags = AI_NUMERICSERV; /* Allow only numeric port numbers */
+  } else {
+    memset(&direct_addr, 0, sizeof(direct_addr));
+    direct_addr.sin_family = AF_INET;
+    direct_addr.sin_port = htons(used_port);
+    direct_addr.sin_addr = *ip_addr;
+  }
 
   instant_t start_connect = lf_time_physical();
   // while (!_lf_termination_executed) { // Not working...
@@ -240,30 +244,43 @@ int connect_to_socket(int sock, const char* hostname, int port) {
       lf_print_error("Failed to connect with timeout: " PRINTF_TIME ". Giving up.", CONNECT_TIMEOUT);
       break;
     }
-    // Convert port number to string.
-    char str[6];
-    snprintf(str, sizeof(str), "%u", used_port);
 
-    // Get address structure matching hostname and hints criteria, and
-    // set port to the port number provided in str. There should only
-    // ever be one matching address structure, and we connect to that.
-    if (getaddrinfo(hostname, (const char*)&str, &hints, &result)) {
-      lf_print_error("No host matching given hostname: %s", hostname);
-      break;
+    if (ip_addr != NULL) {
+      // Safe to type cast specific protocols (e.g., sockaddr_in) to the generic sockaddr.
+      ret = connect(sock, (struct sockaddr*)&direct_addr, sizeof(direct_addr));
+    } else {
+      // Convert port number to string.
+      char str[6];
+      snprintf(str, sizeof(str), "%u", used_port);
+
+      // Get address structure matching hostname and hints criteria, and
+      // set port to the port number provided in str. There should only
+      // ever be one matching address structure, and we connect to that.
+      if (getaddrinfo(hostname, (const char*)&str, &hints, &result)) {
+        lf_print_error("No host matching given hostname: %s", hostname);
+        break;
+      }
+      ret = connect(sock, result->ai_addr, result->ai_addrlen);
+      freeaddrinfo(result);
     }
-    ret = connect(sock, result->ai_addr, result->ai_addrlen);
+
     if (ret < 0) {
       lf_sleep(CONNECT_RETRY_INTERVAL);
       lf_print_warning("Could not connect. Will try again every " PRINTF_TIME " nanoseconds. Connecting to port %d.\n",
                        CONNECT_RETRY_INTERVAL, used_port);
-      freeaddrinfo(result);
       continue;
     } else {
       break;
     }
   }
-  freeaddrinfo(result);
-  lf_print_info("Connected to %s:%d.", hostname, used_port);
+
+  if (ip_addr != NULL) {
+    char host_str[INET_ADDRSTRLEN];
+    inet_ntop(AF_INET, ip_addr, host_str, INET_ADDRSTRLEN);
+    lf_print_info("Connected to %s:%d.", host_str, used_port);
+  } else {
+    lf_print_info("Connected to %s:%d.", hostname, used_port);
+  }
   return ret;
 }